src/Tools/Code/code_namespace.ML

factored out generic part of Scala serializer into code_namespace.ML

(*  Title:      Tools/Code/code_namespace.ML
    Author:     Florian Haftmann, TU Muenchen

Mastering target language namespaces.
*)

signature CODE_NAMESPACE =
sig
  datatype 'a node =
      Dummy
    | Stmt of Code_Thingol.stmt
    | Module of ('a * (string * 'a node) Graph.T);
  val hierarchical_program: (string -> string) -> { module_alias: string -> string option,
    reserved: Name.context, empty_nsp: 'b, namify_module: string -> 'b -> string * 'b,
    namify_stmt: Code_Thingol.stmt -> string -> 'b -> string * 'b,
    cyclic_modules: bool, empty_data: 'a, memorize_data: string -> 'a -> 'a }
      -> Code_Thingol.program
      -> { deresolver: string list -> string -> string,
           hierarchical_program: (string * 'a node) Graph.T }
end;

structure Code_Namespace : CODE_NAMESPACE =
struct

(* hierarchical program structure *)

datatype 'a node =
    Dummy
  | Stmt of Code_Thingol.stmt
  | Module of ('a * (string * 'a node) Graph.T);

fun hierarchical_program labelled_name { module_alias, reserved, empty_nsp,
      namify_module, namify_stmt, cyclic_modules, empty_data, memorize_data } program =
  let

    (* building module name hierarchy *)
    fun alias_fragments name = case module_alias name
     of SOME name' => Long_Name.explode name'
      | NONE => map (fn name => fst (yield_singleton Name.variants name reserved))
          (Long_Name.explode name);
    val module_names = Graph.fold (insert (op =) o fst o Code_Printer.dest_name o fst) program [];
    val fragments_tab = fold (fn name => Symtab.update
      (name, alias_fragments name)) module_names Symtab.empty;
    val dest_name = Code_Printer.dest_name #>> (the o Symtab.lookup fragments_tab);

    (* building empty module hierarchy *)
    val empty_module = (empty_data, Graph.empty);
    fun map_module f (Module content) = Module (f content);
    fun change_module [] = I
      | change_module (name_fragment :: name_fragments) =
          apsnd o Graph.map_node name_fragment o apsnd o map_module
            o change_module name_fragments;
    fun ensure_module name_fragment (data, nodes) =
      if can (Graph.get_node nodes) name_fragment then (data, nodes)
      else (data,
        nodes |> Graph.new_node (name_fragment, (name_fragment, Module empty_module)));
    fun allocate_module [] = I
      | allocate_module (name_fragment :: name_fragments) =
          ensure_module name_fragment
          #> (apsnd o Graph.map_node name_fragment o apsnd o map_module o allocate_module) name_fragments;
    val empty_program = Symtab.fold (fn (_, fragments) => allocate_module fragments)
      fragments_tab empty_module;

    (* distribute statements over hierarchy *)
    fun add_stmt name stmt =
      let
        val (name_fragments, base) = dest_name name;
      in
        change_module name_fragments (fn (data, nodes) =>
          (memorize_data name data, Graph.new_node (name, (base, Stmt stmt)) nodes))
      end;
    fun add_dependency name name' =
      let
        val (name_fragments, base) = dest_name name;
        val (name_fragments', base') = dest_name name';
        val (name_fragments_common, (diff, diff')) =
          chop_prefix (op =) (name_fragments, name_fragments');
        val (is_module, dep) = if null diff then (false, (name, name'))
          else (true, (hd diff, hd diff'))
        val add_edge = if is_module andalso not cyclic_modules
          then (fn node => Graph.add_edge_acyclic dep node
            handle Graph.CYCLES _ => error ("Dependency "
              ^ quote name ^ " -> " ^ quote name'
              ^ " would result in module dependency cycle"))
          else Graph.add_edge dep
      in (change_module name_fragments_common o apsnd) add_edge end;
    val proto_program = empty_program
      |> Graph.fold (fn (name, (stmt, _)) => add_stmt name stmt) program
      |> Graph.fold (fn (name, (_, (_, names))) => fold (add_dependency name) names) program;

    (* name declarations *)
    fun make_declarations nsps (data, nodes) =
      let
        val (module_fragments, stmt_names) = List.partition
          (fn name_fragment => case Graph.get_node nodes name_fragment
            of (_, Module _) => true | _ => false) (Graph.keys nodes);
        fun modify_stmt (Stmt (Code_Thingol.Datatypecons _)) = Dummy
          | modify_stmt (Stmt (Code_Thingol.Classrel _)) = Dummy
          | modify_stmt (Stmt (Code_Thingol.Classparam _)) = Dummy
          | modify_stmt stmt = stmt;
        fun declare namify modify name (nsps, nodes) =
          let
            val (base, node) = Graph.get_node nodes name;
            val (base', nsps') = namify node base nsps;
            val nodes' = Graph.map_node name (K (base', modify node)) nodes;
          in (nsps', nodes') end;
        val (nsps', nodes') = (nsps, nodes)
          |> fold (declare (K namify_module) I) module_fragments
          |> fold (declare (namify_stmt o (fn Stmt stmt => stmt)) modify_stmt) stmt_names;
        val nodes'' = nodes'
          |> fold (fn name_fragment => (Graph.map_node name_fragment
              o apsnd o map_module) (make_declarations nsps')) module_fragments;
      in (data, nodes'') end;
    val (_, hierarchical_program) = make_declarations empty_nsp proto_program;

    (* deresolving *)
    fun deresolver prefix_fragments name =
      let
        val (name_fragments, _) = dest_name name;
        val (_, (_, remainder)) = chop_prefix (op =) (prefix_fragments, name_fragments);
        val nodes = fold (fn name_fragment => fn nodes => case Graph.get_node nodes name_fragment
         of (_, Module (_, nodes)) => nodes) name_fragments hierarchical_program;
        val (base', _) = Graph.get_node nodes name;
      in Long_Name.implode (remainder @ [base']) end
        handle Graph.UNDEF _ => error ("Unknown statement name: " ^ labelled_name name);

  in { deresolver = deresolver, hierarchical_program = hierarchical_program } end;

end;